Author Topic: CB400 Four special (Mr Sinx II )  (Read 245 times)

Offline Northy

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CB400 Four special (Mr Sinx II )
« on: October 09, 2018, 08:02:44 PM »
Right any purist please look way now before you go mad and say why wreck cb400f and make special out of it .

OH also long thread alert …if your bored just look at the pictures ;-) Oh will be lots of typos as well   :D

Why a 400 four ,well back in 70/80 I created this and number of variations and still had standard yellow one VKK 333S.


 I sold the bike in 1993  for £350 plus a mountain of spares (DOH !! ) well the engine had done over 150k, was on its second frame, iffy wiring and even the ARE alloy wheels where a bent in places. Ironically nothing I couldn’t fix now. So some 30 yrs on , my spannering skills are better than that poor cheeky kid on the “flying tampon” as mates  used to call it. Its was called Mr Sinx, after our cat (bloody vicious thing!)

Well at the time of writing I have two other 400f that are rolling restorations. 2 frames and yet another mountain of part worn 400 bits. Also over the last few years done a few restoration to high standard and a couple of specials.(read I’m handy with spanner and a picky sod too)

So this will be a recreation of Mr Snix but I might move away from the clip ons etc , so more like the Mocheck Harrier (to save my back & wrists). So I’ve already have picture of how it will look in my head and I know what I need but finding them and making them fit is the fun bit  (need a set of Alloys)   

So where does ones start with just frame, engine and plie of bits …the carbs of course. I needed a clean set for one of the other bike which was suffering odd running.(turned out to be the coils). The Bike bits had been sitting for excess of 7yrs in  garage (working one with sooty diesel, brake dust and damp etc )  So the carb where stripped right down 




Tip one , don’t disassemble the rod mechanism if don’t have to. The rod that runs across the carbs to link them together runs in two bronze bushes. However there is also a brass pin in one mount that hold the bush in place and locates pin on the rod. To remove the rod you need to drill out this brass pin or the bush with break up if you try to remove the rod. However drilling out the pin a PTA its only 3mm dia and can easy go into the ally mounting. See picture even drilling the pin didn’t help cracked anyway!!
So some clean carbs , a with re-plated metal bits. I used stainless bolts and this not going to standard anyway.

 
Good job I've spare set of carbs

So next engine, I wasn’t expecting great things from this. The clock said it had done 43,000 miles and it showed signs of previous split cases and nasty bodges. As I was  stripping this down to last bits, I didn’t bother deep cleaning it before hand


Ohh err


The thread on bolt that locks cam chain adjuster had been chewed up badly but managed to heli coil it. Phew

Spot the odd one out


Two head bolt where finger tight and the cam chain was starting chew its way into the adjuster (they all do that sir). Which is why there was no wear on the guides.
Then the good news the clutch looked like new. I even found my old home made clutch holding tool in the not use often “tool box” last used  25 yrs ago



The primary chain, is very sloppy and need a new one of those. The bore was OK , with marking where the piston had been and still on standard piston bit all looking a bit tied with one broken ring. I measured them all up and there just outside the recommended tolerances, could put new std piston and new rings  and it would run but it deserves a rebore.





So do I go for the oversized 54mmbore kit or just take it 0.25mm OS. The cost using kits from Cruzinimage_uk is the same. I tempted by the big bore (sounds good and gains brownie point when talking bollocks at the cafe)  but then reality kicks in and its only  on a 400  if I need to go faster there’s an modern 750 in garage.   However welcome your thought on this ??.


There was much sludge in sump and bottom of the cases but hardly any metal bits …all good.

Main bearings all Ok but the big end showing wear so they will be replaced ….bloody expensive at £10.74  per half shell ….


All the valves have been removed and the head looks in fine shape no damaged fins, rocker spindles with bit of wear and valve seats good.Cams  all good , wear but nothing  bad.
So no sheared screws or bolts, expect general wear no nasty surprises and only two threads required a helicol. I do them when I see on strip down as the stuff is going to be cleaned after so any bits of ally get washed away.  Not bad at all it would have run no doubt but no very well.

Tip 2  Rotor removal is required for replace the end seal and best  done once the crank removed,. you can’t do without splitting the cases due to the lip on the seal. You could take a hammer to it, dig out the special tool (if you have one ) with a 18x1.5 thread it to “pull” the rotor  off. However the thread a size is the same of many car sump plug or Lamaba sensor plugs available for £2.  Sorted !!   


Next ……the case of clean the cases!!
     
Got quoted £140  to vapour blast the  cases,head. barrels etc  .......Sod that, out with chemicals.
« Last Edit: October 15, 2018, 09:08:53 PM by Northy »
How many is too many bikes ..... when you have no space left.

Offline SumpMagnet

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Re: CB400 Four special (Mr Sinx II )
« Reply #1 on: October 09, 2018, 08:19:21 PM »
Personally..I have no issue with someone restoring an old bike in a less than standard way. The way I see it, you have put another old bike back on the road, rather than let it rust away in a shed somewhere. Or worse...restored it and then stuck it on a turntable never to run again...just to be looked at.

Back in the day, I hardly ever had a 'stock' bike and instead had aftermarket seats, bars, fairings, shocks, fork braces and all the other tat the fashion trends said you had to have.

On top of that...you are making something personal to you....Hope it ends up as good as you remember!

CB750F2 - in pieces
CB900F Hornet - the daily transport

Online Trigger

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Re: CB400 Four special (Mr Sinx II )
« Reply #2 on: October 09, 2018, 08:55:12 PM »
Nowt wrong with those crank case shells from the picture, measure them up  ;) Much cheaper than new ones  ;D

Offline Northy

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Re: CB400 Four special (Mr Sinx II )
« Reply #3 on: October 09, 2018, 10:36:03 PM »
its big end that have gone ...I'll  get some piccy's of those.
 
How many is too many bikes ..... when you have no space left.

Offline Bryanj

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Re: CB400 Four special (Mr Sinx II )
« Reply #4 on: October 10, 2018, 01:17:05 AM »
If the cranks worn its toast cos you cant regrind them or rather if you do there are no shells made

Offline Northy

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Re: CB400 Four special (Mr Sinx II )
« Reply #5 on: October 14, 2018, 05:12:06 PM »
Crank is good , see piccy

[/URL]][/img]

Big ends look like this , worn but nothing nasty
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Just new shells needed.All david silver was offering  at stafford was £1 delivery for order placed at the show and I've long list of stuff I need could remember it all.

Set of cases nearly ready for painting , mainly used paint striper , small wire bush  attachment , then wash in thinner , will need another clean [/URL][/img]

Been working on the manky side covers ...getting there slowly
[/URL][/img]





« Last Edit: October 15, 2018, 09:11:17 PM by Northy »
How many is too many bikes ..... when you have no space left.

Offline Northy

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Re: CB400 Four special (Mr Sinx II )
« Reply #6 on: November 12, 2018, 05:35:38 PM »
Ok having be side tracked with decorating time , its time to move on with Mr Snix

Ok cases clean up,



Sprayed , gloss black , used Hycote engine enamel  not too bad and re-plated my engine bolts  but  they just would shine up very well , suspect too cold a solution, the angle held in electrolyte and they were rough to start with.



Having sussed out then I had Yellow big end shells (oh or misses) I was going to go like for like as they weren’t that worn but suspect that I could go up to green set. I re-measured and seemed to playing for ever with plastigauge, clever but all  doing up  undo , do up undo  etc etc is PITA  and  all  to confirm my initial thought and go for green. So a large order was placed with Mr Silver. Luckily in the stash of shares was a new cam chain, two guides but no primary chain.


The head showing signs of the broken ring on No 2  pot  but nothing scary
[/URL][/img]
Note the heads not be been cleaned properly at this piont,and will take a skim off the head. 
 

Here’s  a thing valve collets, they must the experts in sod’s law , get one and the other falls out. Normally I  work of Guzzi heads and there massive compared to the 400.   

Here my tool for grinding in valves, then car rubber sucker ones just too big  for tiny 400 valves   
   

Whilst waiting for engine paint go off and waiting on spares, I turned my attention to the frame. I’ve choice of F1 or F2  frame, so which  one  to use. The biggest factor was the F2 had  a log book , still to apply to F1  frame. 
The ultimate in  a 400 special is a 4 into 4  system and thus the F1  frame might be better one to  do that with, however having had  4 into  4 fitted in past it was PITA  and reduced my ground clearance  to zero.
The lay out the sump/ frame etc  makes it hard to do, So its 4 into 1  it is for this baby.

So F2 frame is stripped and then I started on rear sets, using the old pair of tarozzio rear sets and mount plates in my spares stash. It’s all rough and ready at this point just  to ensure everything works. So its looks a bit rusty and manky at present.


Next for frame is a  “new “  set of forks of  CB400N   ie double disc and box section swing arm,(Note that brand new dresda box section one sold for over £200 on evil bay ) and may need some wheels .

It’s going have ally wheels and not comstars and as Maitland racing no long stock ARE (ally racing eqpt) wheels that were made in Cardiff in early 80’s .  I did ask !!! it was what Mr Snix had originally fitted.   So it will have a double discs and maybe even a rear one.

As  for wheels I have set of GPZ400 lying around and the front wheel popped onto the CB400N forks easy, same spindle size and just need to mill down the space a bit each side . However the Discs might not line up with the any calipers. So which muppet sold the GPZ400 ones on ebay a year ago. I suspect I might go for a set of modern calipers.



The rear wheel is different matter ,the GPZ400 wheel has a massive rear disc and the hub is plain too fat and would need to remove 7 mm from the sprocket carrier ,not in impossible but would remove to much ally on the carrier . Added to this just doesn’t fit well with the overall look of the bike , the massive disc  and hub


So I’ll be paying a visit to local bike breakers , with a tape measure, looking for  set of wheels, swing arm, brakes  etc. That will be messy as Larry’s place is not known for clean washed parts (they go in dirty and get dirtier) and much hunting.i.e Honda wheels – “ in that pile over there”

Then the fun starts and it should easier to play the  frame without an the engine in it (noting sprocket alignment)   

OH BTW  Rock horse poo item . clutch adjuster
 


How many is too many bikes ..... when you have no space left.